1. Field of the Invention
The present general inventive concept relates to a developing cartridge and an image forming apparatus including the same, and more particularly, to a developing cartridge capable of easily attaching and detaching accommodated components.
2. Description of the Related Art
In general, an electrophotographic image forming apparatus forms an image on a printing medium through a series of charging-exposure-developing-transferring-fusing processes. The electrophotographic image forming apparatus generally comprises a developing cartridge that is detachably provided to store toner.
As illustrated in FIGS. 1 and 2, a conventional developing cartridge 1 is provided with a supporting casing 10, a cover casing 20, a right side frame 30, a left side frame 40, and an accommodated component 50 which is accommodated in the supporting casing 10.
As illustrated in FIGS. 1 and 2, an upper side of the supporting casing 10 is opened so as to mount the accommodated components 50 to be described later. Also, on a lower side of the supporting casing 10 is formed a transfer opening 18 so that toner on a surface of a photosensitive body 155 can be transferred to a printing medium while a developing cartridge 1 is operated, the surface of the photosensitive body 55 being exposed to the outside.
The cover casing 20 covers up an opening of an upper side of an accommodating main body 11 of the supporting casing 10, and forms a waste toner storing room 5 on a first side, and forms a toner storing room 3 on a second side. Between the two rooms is disposed a sealing member 54 to prevent toner and waste toner accommodated in the toner storing room 3 and the waste toner storing room 5 from being leaked. Referring to 58a and 58b in FIG. 2, a sealing film is provided to be in contact with a developing roller 52 and a photosensitive body 55 to seal the toner storing room 3 and the waste toner storing room 5.
The accommodated component 50 comprises a photosensitive body 55 on which an electrostatic latent image is formed by exposure, a charging roller 51 which charges the surface of the photosensitive body 55 to a predetermined electric potential, a developing roller 52 which develops the electrostatic latent image with toner, a supplying roller 56 which is accommodated in the toner storing room 3 to supply toner to the developing roller 52 and frictionally charge the toner, and a cleaning unit 53. The reference numerals 57a and 57b in FIG. 2 denote a doctor blade and a bracket that supports the doctor blade. The description of the mounting method of the doctor blade 57a and the bracket 57b will be omitted, as it is the same as that of the cleaning unit 53.
As illustrated in FIG. 2, the cleaning unit 53 is provided with a cleaning blade 53a which scrapes and cleans waste toner remaining on a surface without being transferred, being in contact with the surface of the photosensitive body 55, and a supporting plate 53b which supports the cleaning blade 53a. 
Here, the developing cartridge 1 is assembled in an order of an accommodated component 50 installing process for arranging or mounting the accommodated component 50 in/to the supporting casing 10, and the cover casing 20 coupling process for seal-coupling the cover casing 20 to the supporting casing 10 by the sealing member 54.
Finally, the right side frame 30 and the left side frame 40 are coupled to sides of the supporting casing 10. Accordingly, the position of some accommodated components 50, 52, 55, and 56 disposed inside the supporting casing 10 in a temporarily-mounted state is determined, and then the developing cartridge 1 is completed.
As illustrated in FIG. 1, the accommodated component 50 is installed in the supporting casing 10 in a direction from an upper side to a lower side M. As illustrated in FIG. 2, the supplying roller 56 is disposed in the supplying roller accommodating room 56S, the photosensitive body 55 is disposed on the photosensitive body supporting plate 13 (FIG. 2), and the developing roller 52 is disposed between the photosensitive body 55 and the supplying roller 56. The supplying roller 56, the photosensitive body 55, and the developing roller 52 are in a temporarily-mounted state, and their positions are determined after the side frames 30 and 40 (to be described later) are coupled.
Meanwhile, as illustrated in FIG. 5, the cleaning unit 53 is mounted to a cleaning supporting unit 17 provided on opposite sides of a lengthwise direction of the cleaning unit 53 of the accommodating main body 11 by a coupling unit U.
Also, as illustrated in FIGS. 3 and 4, the charging roller 51 is mounted to charging roller supporting units 12L and 12R that are provided on right and left sides of the accommodating main body 11.
The charging roller supporting units 12L and 12R (FIG. 3) have a through hole 12a through which a charging roller shaft 51a can pass. The through hole 12a has a groove 12b corresponding to a separation preventing projection 7a of a charging roller shaft bushing 7. Also, as illustrated in FIG. 4, the charging roller shaft bushing 7 has a lower side that is opened in a direction in which the charging roller shaft 51a is inserted. Also, the charging roller shaft bushing 7 has the separation preventing projection 7a to prevent the charging roller shaft bushing 7 from being separated in an axial direction.
First, first end portions of two coil springs 6 are coupled to a coupling projection 12c of the right and the left charging roller supporting units 12L and 12R. Then, second end portions of the coil springs 6 are coupled with the charging roller shaft bushing 7, respectively. Thereafter, opposite end portions of the charging roller shaft 51a are inserted into the charging roller shaft bushing 7.
However, as illustrated in FIG. 4, since the coil springs 6 apply an elastic force to the charging roller shaft bushing 7 downwardly, one end portion of the charging roller shaft 51a is first inclined to be inserted into the charging roller shaft bushing 7, and then the other end portion is inclined to be inserted into the other side charging roller shaft bushing 7 in the inserted state, thereby the charging roller 51 being mounted completely.
Meanwhile, as illustrated in FIGS. 1 and 2, after the installing process of the accommodated component 50 is finished, the cover casing 20 is coupled to the supporting casing 10. Also, the sealing member 54 is disposed between the cover casing 20 and the supporting casing 10 along the border of the waste toner storing room 5 and the toner storing room 3.
After the cover casing 20 is coupled, the side frames 30 and 40 are coupled to the right and the left side of the accommodating main body 11, respectively. Since the left side frame 40, for example, is the same as the right side frame 30, only the right side frame 30 will be described hereinafter.
As illustrated in FIG. 3, in the right side frame 30 are formed a photosensitive body inserting boss 31, and a supplying roller shaft hole 35 which rotationally supports a supplying roller shaft (not illustrated) projected on the side of the accommodating main body 11. The photosensitive body inserting boss 31 passes through a main body position determining hole 14R of the accommodating main body 11 to be inserted into a photosensitive body shaft hole 55a (FIG. 1).
Also, in the right side frame 30 is provided a developing roller position determining unit 33 which determines a position of a right end portion of the developing roller shaft 52a. In the developing roller position determining unit 33 is provided an accommodating room 33a that accommodates a right end portion of the developing roller shaft 52a and a developing roller shaft bushing (not illustrated) into which the right end portion of the developing roller shaft 52a is inserted. Also, between the developing roller shaft bushing (not illustrated) and the spring supporting projection 33b, is disposed a coil spring (not illustrated) to elastically support the developing roller 52 toward the photosensitive body 55.
The position determining projection 32 of the right side frame 30, the photosensitive body inserting boss 31, the supplying roller shaft hole 35 and the developing roller position determining unit 33 are inserted into the position determining hole 15 of the accommodating main body 11, the photosensitive body shaft hole 55a in the temporarily-mounted state, the supplying roller shaft (not illustrated), and the developing roller shaft 52a, respectively. Accordingly, the position of the rotational center of the accommodated components 55, 56 and 52 which have been in the temporarily-mounted state is determined. Here, the position determining hole 15 is provided in the shape of a long hole in a transverse direction (refer to J in FIG. 7) of the accommodating main body 11, and although the photosensitive body inserting boss 31 is inserted into the main body position determining hole 14R, the relative position of the right side frame 30 can be precisely controlled.
Further, a bolt is inserted to and couples the coupling holes 34b and 16b formed in the right side frame 30 and the accommodating main body 11 respectively, thereby detachably coupling the components.
However, if an inferior component is detected among the accommodated components after the cover casing 20 is coupled to the supporting casing 10 in a manufacturing process of the conventional developing cartridge 1, or if an inferior component is detected among the accommodated components during using the developing cartridge 1, the cover casing 20 needs to be opened for replacing the inferior component. Also, since the sealing member 54 needs to be mounted again after the accommodated component 50 is replaced, it is not easy to replace the accommodated component 50. Accordingly, an assembling time and a component cost for the developing cartridge 1 may increase.
Also, as described above, the charging roller shaft 51a is inclined so that the charging roller 51 can be mounted, thereby lowering an assembling operation efficiency and increasing an assembling time. Also, since the mounting process of the charging roller 51 is complicated, it cannot be automated by a robot. Accordingly, it is difficult to automate an assembling process of the developing cartridge 1.